A study of different biometrie data of populations of Uroleucon (U.) picridis (F., 1775) sensu lato using canonical discriminant analysis resulted in the separation of two morphological groups. Exchange of host plants allowed us to conclude that the two groups correspond to two different species: Uroleucon (U.) picridis and Uroleucon (U.) mierae sp.nov. This latter species was described and a key to the identification of both species was given.

Warren rootcollar weevil, Hylobius warreni Wood, is a pest of several conifer species and is distributed widely throughout the boreal forest in Canada. Literature on this weevil is reviewed and interpreted to provide comprehensive coverage of its ecology, behavior, and impacts, and the implications for its management. New information is provided to fill gaps in our knowledge of H. warreni. These include distribution and hosts, immature stages, sex ratios, and daily and seasonal activity patterns of adults. Sex ratios, abundance, longevity, and pedestrian dispersal behavior of adults within the forest and on trees are described from mark, release, and recapture studies conducted over several years using a newly designed interception trap. Daily trap captures are correlated with previous night temperatures and this relationship is a tool for predicting adult captures. Fecundity and oviposition behavior on the host tree are described from laboratory- and field-reared adults.

Population levels of H. warreni are compared across a variety of lodgepole pine stands in Alberta. Weevil numbers within forests are described in relation to tree size and age, depth of duff material around tree bases, and stand density. Analysis of weevil feeding scars distributed at the root collar base of mature pine stems were used to describe the likely temporal pattern of population abundance and change during stand development. Information supportive of this pattern is presented from surveys in young and mature stands.

A new method of assessing stands of lodgepole pine for suitability of habitat for H. warreni takes into account the cumulative nature of this weevil’s injury and reflects its temporal pattern of success in relation to stand conditions. The effects of a pre-commercial thinning treatment on H. warreni populations and its girdling injury were investigated in a 25-year-old lodgepole pine stand over an 8-year period. Compared with control plots, thinning treatment caused a 5-fold increase in weevil numbers per tree and increased the tree attack incidence by 2-fold, but resulted in an average 6% reduction in partial stem girdling of attacked trees. Information about the effects of various forest management practices on H. warreni abundance and survival is reviewed and areas requiring research are identified.

Cuticular damage of Spodoptera exigua (Hübner) pupae, caused by puncturing with a sterilized insect pin, resulted in enhanced susceptibility to the entomopathogenic nematode Steinernema carpocapsae (Weiser), but cold shock (5 °C for 24 h) did not alter susceptibility. The additional avenue of entry for the nematode probably accounted for the increased mortality of the damaged pupae. In all treatments, some dead pupae contained Xenorhabdus nematophilus (Poinar and Thomas), the symbiotic bacterium of S. carpocapsae, but no nematodes. More nematode-killed pupae containing X. nematophilus but no nematodes were found in the cold-shock treatment than in the room-temperature control (62.6 versus 46.9%). In contrast, fewer nematode-killed pupae containing X. nematophilus but no nematodes were found in the damaged pupae compared with the undamaged control (25.0 versus 45.1%). Moreover, mortality of nematodes within the cadavers of cold-shocked insects was higher than in the cadavers of non-cold-shocked insects. These results suggest that the stressors, cold shock and cuticular damage, produce fundamentally different responses in insects exposed to them, and that the physiological state of the insect greatly influences nematode survival in the host and hence nematode recycling in the environment.

Temperature-dependent development of eggs, larvae, and pupae of the speckled green fruitworm, Orthosia hibisci Guenée, at constant temperatures of 5–30.0 °C, 7.5–27.5 °C, and 0.8–20.8 °C, respectively, was described. Development times decreased with increasing temperatures and minimum developmental times in eggs, larvae, and pupae occurred at ca. 27.5, 25, and 20.8 °C, respectively. Variation in development times of all life stages was modelled accurately (R2 values 0.98–0.99) with a Weibull distribution. Relationships between temperature and developmental rates of all life stages were described by linear degree-day (DD) and nonlinear poikilotherm models. There were significant differences (ANOVA, P < 0.05) among the slopes of regression equations describing developmental rates of different life stages and larval instars. Minimum developmental temperatures for eggs (3.4 °C), first- through fifth-instar larvae (4.7, 2.9, 3.6, 3.5, and 3.7 °C), and pupae (2.8 °C) were determined by extrapolation of linear regression equations to the x-intercept. Median development time of eggs, first- through fifth-instar larvae, and pupae required 99.0, 44.2, 51.5, 52.4, 57.1, 69.9, and 61.3 DD above the minimum developmental temperatures, respectively. Developmental rates of eggs and all larval instars averaged were described by six-parameter models exhibiting low- and high-temperature inhibition. Development of pupae was best described by a four-parameter model exhibiting low- but no high-temperature inhibition. This information should be useful for developing a phenology model to improve management actions against O. hibisci.

Neosymydobius neomexicanus sp.nov., N. peregrinus sp.nov., N. acutipilosus sp.nov., N. rumorosensis sp.nov., and N. paucisetosus sp.nov. are described and their relationship with other species is discussed. A lectotype of N. agrifoliae (Essig) was chosen from Essig’s type specimens. The taxonomic position of Neosymydobius is evaluated and a key for the identification of the presently known species is presented.

The effect of greenbug, Schizaphis graminum (Rondani), infestations on yield components of early- and late-planted spring wheat, Triticum aestivum L., were measured in 2 successive years in eastern South Dakota. Greenbug populations in plots generally increased rapidly and peaked when wheat plants were in boot stage. Populations then began a steady decrease until anthesis, at which time they were near zero. The number of seeds per spikelet and the number of spikelets per square metre were consistently significantly negatively correlated with aphid-days, whereas average seed weight was significantly negatively correlated with aphid-days for only one planting. A linear regression model that included different intercepts for each spring wheat planting and a common slope relating yield to greenbug feeding days (aphid-days) provided a good fit to the data. Based on the model, a loss of 41 kg of grain per hectare is expected for each 100 aphid-days that accumulate per tiller.

Eversible sacs (= "scent organs" or "eversible tubes" or "eversible glands" of previous authors) are present in the abdomens of females of species of Stenoxenus Coquillett, Paryphoconus Enderlein, Clastrieromyia Spinelli and Grogan, Bezzia Kieffer, Phaenobezzia Haeselbarth, Amerohelea Grogan and Wirth, Pachyhelea Wirth, and Palpomyia Meigen. In Bezzia varicolor (Coquillett) they are attached by muscles to dorsal internal tergal apodemes. When retracted, the sacs lie along the length of the apodemes. Suggested functions of the eversible sacs have ranged from roles in mating, mimicry of adult mayfly cerci to enhance predation, to glandular. However, histological examination showed no evidence of glandular tissue associated with the sacs, so a glandular function is discounted. We suggest other possible functions.

There are 16 species of Trichoclinocera Collin recognized from the Nearctic region, including eight new species. Four of six species-groups of Trichoclinocera are recognized in the Nearctic region, with the following included species: (1) T. comata group — T. cascadensis sp.nov. (type-locality Starvation Creek, Oregon, U.S.A.), T. comata (Melander) comb.nov., and T. rupestris sp.nov. (type-locality Newton Creek, Wyoming, U.S.A.); (2) T. dolicheretma group — T. dolicheretma (Melander); (3) T. lapponica group — T. lapponica (Ringdahl) comb.nov.; (4) T. longipes group — T. agilis sp.nov. (type-locality Fall Creek Falls, Tennessee, U.S.A.), T. ctenistes (Melander), T. dasycoxa sp.nov. (type-locality Ottawa, Ontario, Canada), T. falcata sp.nov. (type-locality Gatineau Park, Quebec, Canada), T. fumosa (Vaillant) comb.nov., T. hamifera (Melander), T. longipes (Walker). T. minor (Melander), T. ozarkensis sp.nov. (type-locality Haw Creek Falls, Arkansas, U.S.A.), and T. pectinifemur sp.nov. (type-locality Phoenixville, Pennsylvania, U.S.A.). The following new synonyms are proposed: T. brunnipennis (Melander) = T. dolicheretma; and Seguyella saltans (Vaillant) = T. hamifera. Lectotypes are designated for T. comata, T. ctenistes, T. dolicheretma, T. brunnipennis, T. hamifera, T. lapponica, and T. stackelbergi Collin. Seguyella Vaillant and Acanthoclinocera Saigusa are newly synonymized with Trichoclinocera and all species formerly placed in these genera are transferred to Trichoclinocera, except Acanthoclinocera glaucescens (Brunetti) which is transferred as Wiedemannia glaucescens (Brunetti) comb.nov.This revision includes a key to Nearctic species, a description of each species, and maps of species distributions. Homologies of male terminalia of Clinocerinae are summarized and the first descriptions of the immature stages of species of Trichoclinocera also are provided. A world list of described species of Trichoclinocera is provided and all species are assigned to one of six species-groups, except T. cummingi sp.nov. (type-locality Robber’s Cave, Oklahoma. U.S.A.), T. fluviatilis (Brunetti) comb.nov., T. fuscipennis Saigusa, and T. maewa Smith, which remain unplaced. The monophyly of Trichoclinocera is justified and phylogenetic relationships to the remaining Clinocerinae and among species-groups are discussed.

The relationship between temperature and pathogenesis of Bacillus thuringiensis Berliner var. kurstaki in infected larvae of the eastern spruce budworm, Choristoneura fumiferana Clem., was investigated to determine if more rapid death of larvae with an increase in temperature could be accounted for by enhanced bacterial growth. Cumulative mortality of larvae force-fed with a lethal dose of HD-1-S-1980 peaked within 2 days at 25 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C. The progress of bacterial growth in the larvae was followed from spore germination to cell lysis, and was completed within 4 days at 25 °C, 6 days at 22 °C, 12 days at 19 °C, 14 days at 16 °C, and > 28 days at 13 °C. Peak abundance of vegetative cells in the larvae was observed after 1 day at 25 °C, 2 days at 22 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C, and thus coincided almost exactly with the time required for maximum larval mortality. This correlation suggests that the observed effect of temperature on progression of larval mortality was due to its effect on the proliferation of vegetative cells in the infected larvae, and that bacterial septicemia makes an important contribution to death.

The pine engraver, Ips pini Say, and Pityogenes knechteli Swaine often co-exist in lodgepole pine, Pinus contoita var. latifolia Engelmann. We tested the hypotheses that P. knechteli produces an attractive pheromone and that the attraction of P. knechteli and I. pint to conspecifics is inhibited by the presence of the other species. Pityogenes knechteli males and females were attracted to bolts infested with conspecific males and to bolts infested with I. pini males; however, there was no significant cross-attraction of I. pini males or females to bolts infested with P. knechteli males. Attraction of P. knechteli and I. pint males and females to bolts infested with conspecific males was not inhibited in the presence of bolts infested with males of the other bark beetle species. Pityogenes knechteli has no potential for competitive displacement of I. pini but may enhance the adverse effect of I. pini on the mountain pine beetle, Dendroctonus ponderosae Hopkins.

A brief biography of a little-known Hanoverian entomologist, Johann Dietrich Herschel (1755–1827), is given. The more important events of his life, his entomological interests, and his relationships to other entomologists are covered. Included is a table of the species of beetles known to have been described from his collection by several entomologists of the late-18th and early-19th centuries.

A new, broader concept of the genus Aradophagus Ashmead is presented to include Abuko Masner and Huggert and Ladora Masner and Huggert (new synonyms). The extent of the tribe Aradophagini is discussed and some character states re-evaluated. Ladora maura Masner and Huggert is synonymized under Apegus squamosus Dodd (new synonym). The distribution of some species of Aradophagus is discussed. The first fossil member of the genus is reported from late Tertiary amber of Hispaniola (Dominican Republic). Aradophagus diazisp.n ov. is described from Venezuela as the first member of the genus and the tribe in South America. A key to described world species of Aradophagus is presented.

In Canada biological control of grasshoppers has been studied since the 1930s. Previous attempts at "classical" introductions have not been successful. Native parasitoids, especially sarcophagid flies, have a significant impact on grasshopper populations during certain times but the required conditions and regulatory potential are not understood. Sarcophagids, especially Kellymyia kellyi (Aldrich), and the mermithid nematodes Agamermis decaudate Cobb, Steiner, and Christie and Mermis subnigricans Cobb have some potential as inundative agents. Invertebrate predators appear to impact on egg and early-instar nymphal grasshoppers, and vertebrates, especially birds, help to regulate later instars and adults. The role of microbial pathogens in the population dynamics of grasshoppers in western Canada has long been recognized, particularly with regard to entomophthoran fungi. The possibility of utilizing the microsporidan Nosema locustae Canning for suppression of grasshopper populations has been postulated since the 1970s and field evaluations of its potential have been conducted in Saskatchewan and Alberta. More recently, considerable work, both basic and applied, has demonstrated the potential of various fungus isolates pathogenic to grasshoppers as both "classical" and inundative control agents. Entomopoxvirus isolates from grasshoppers also show potential as biological control agents of grasshoppers but this potential has yet to be investigated in field situations. It is clear, however, that no single microbial pathogen will be the panacea of grasshopper control. It is suggested that future biological control research focus on acquiring a better understanding of the requirements and quantitative effects of parasitoids and predators on grasshopper populations. Emphasis should also be placed on developing integrated pest management programs that utilize local natural enemies (nematodes and microorganisms) for inundative control during outbreaks.

Following attack by Dendroctonus brevicomis LeConte, ponderosa pines were periodically sampled over 7 weeks. Xylem water conduction was assessed using a dye flow technique. Fungal isolations were made from functioning and occluded xylem. Neither Ophiostoma nigrocarpum (Davids.) de Hoog or other bluestain fungi were commonly found at the interface of the occluded and functioning xylem. Instead, blue-stain fungi appear to colonize already occluded xylem, not cause xylem occlusion by direct hyphal penetration of functioning sapwood. No evidence for a mutualistic association of D. brevicomis and its vectored bluestain fungi was found.

Available information on the interaction between Sitka spruce weevil, Pissodes strobi (Peck), and its host Sitka spruce, Picea sitchensis (Bong) Carr., is examined. Based on a theoretical consideration of this information, a new mechanism is proposed to explain the resistance exhibited by some of the genetically distinct individuals of some provenances of this species. Experimental evidence is presented to show that resistant trees can sufficiently affect P. strobi reproduction and progeny development and survival to reduce this pest’s ability to kill the leaders of these trees when challenged with weevils containing already mature eggs. Our mechanism also provides an explanation as to how weevils are able to avoid attacking and reproducing on resistant trees in which their progeny would fail.

The Nearctic species of the genus Holoteleia are revised. Two named species are redescribed and five new species are described: H. armigera from Florida; H. coriacea, H. laticeps, and H. polita from eastern Canada and the United States; and H. elegans, widespread east of the Rocky Mountains. A diagnosis of Holoteleia and a key to the Nearctic species are given. Potential impact of environmental degradation on the frequency of Holoteleia species in North America is discussed.

Aspects of the life history of the aphid hyperparasitoid Asaphes vulgaris Walker, when reared on Aphidius nigripes Ashmead, were investigated under laboratory conditions. Longevity was significantly related to temperature and to the sex of adults. Female life span was about 4 months at 15 °C compared with 46 days at 25 °C; under the same conditions male longevity was 66 and 19 days, respectively. Females started to oviposit in aphid mummies upon eclosion and lifetime fecundity was high, reaching 1433 offspring. The sex ratio (proportion of males) was low early in reproductive life but rose sharply after several weeks. The implications of these results on the efficacy of A. nigripes in the potato agrosystem are discussed. It is suggested that high hyperparasitoid fecundity and longevity might play a role in reducing the impact of the primary parasitoid.

A group of subarboreal tropical beetles, the Xystosomi of subtribe Xystosomina new subtribe, is revised and reclassified based on a reevaluation of structural characters. Xystosomi are found in tropical Australia (Queensland) and tropical/subtropical America (Guerrero, México, to Aguas Blancas, Argentina). The largest concentration of species occurs near the equator in the Amazon Basin, but a significant radiation of flightless forms was recently discovered in the northern Andes of Colombia, Ecuador, and Venezuela. Xystosomina also includes the Mioptachyi, which at present is composed of the genera Mioptachys and Inpa.Seventy-six species of Neotropical and Australian Xystosomi are described or re-described, illustrated, or keyed. This assemblage includes 12 classic species, 24 species described in the last 3 decades, and 40 new species, a 6-fold increase since the time of Henry Walter Bates, the last 19th-century entomologist to study this remarkable lineage of carabid beetles. The Xystosomi are now arrayed in five genera: Philipis gen.nov. (type: Tachys trunci Darlington, Australia), Geballusa gen.nov. (type: Xystosomus microtretus Erwin, Costa Rica), Gouleta gen.nov. (type: Bembidion cayennense Dejean, Brazil), Batesiana gen.nov. (type: Xystosomus gruti Bates, Brazil), and Xystosomus Schaum (type: Xystosomus inflatus Schaum, Brazil).The following specific taxa are described as new (type-locality in parentheses): Geballusa rex (Brazil: 06°02′N 050°17′W), oligotreta (Panamá: 08°40′N 079°56′W), nannotreta (Brazil: 02°54′S 059°57′W), Gouleta gentryi (Perú: 12°50′S 069°20′W), Batesiana para (Brazil: 01°22′S 048°20′W), angustia (Perú: 05°08′S 074°45′W), samiria (Perú: 05°08′S 074°45′W), esheje (Perú: 05°08′S 074°45′W), crassa (Perú: 03°15′S 072°55′W), notesheje (Perú: 03°15′S 072°55′W), manusculptilis (Perú: 12°07′S 070°58′W), parapara (Brazil: 02°28′S 046°26′W), am (Perú: 05°08′S 074°45′W), indetecticostis (Ecuador: 00°57′S 077°48′W), nox (Ecuador: 00°57′S 077°48′W), parkeri (Perú: 03°15′S 072°55′W), hamatilis (Ecuador: 01°02′S 077°40′W), notparkeri (Colombia: 00°08′N 075°51′W), pfunorum (Perú: 03°15′S 072°55′W), quadrata (Perú: 03°15′S 072°55′W), protosculptilis (Perú: 12°50′S 069°20′W), misahualli (Ecuador: 01°02′S 077°40′W), depressisculptilis (Ecuador: 01°02′S 077°40′W), irisculptilis (Ecuador: 00°24′S 076°37′W), foveosculptilis (Brazil: 02°28′S 046°26′W), punctisculptilis (Perú: 03°15′S 072°55′W), eugeneae (Perú: 11°56′47″S 071°17′00″W), anchicaya (Colombia: 03°43′N 076°57′W), jefe (Panamá: 09°12′N 079°21′W), exigupunctata (Perú: 05°08′S 074°45′W), rosebudae (Ecuador: 00°57′S 077°48′W), equanegrei (Ecuador: 00°57′S 077°48′W), henryi (Ecuador: 00°28′S 077°53′W), baeza (Ecuador: 00°57′S 077°48′W), huacamayas (Ecuador: 00°28′S 077°53′W), dannyi (Ecuador: 00°57′S 077°48′W), alticola (Colombia: 04°21′S 074°22′W), jacupiranga (Brazil: 24°42′S 048°00′W), chiriboga (Ecuador: 00°15′S 078°44′W), wygo (Colombia: 04°53′N 074°31′W).The following names are resurrected from synonymy for good species: hilaris Bates and belti Bates. Several name combinations were changed as a result of the generic reorganization: Philipis trunci (Darlington), Geballusa microtreta (Erwin), G. polytreta (Erwin), Gouleta notiophiloides (Erwin), G. spangleri (Erwin), G. cayennense (Dejean), Batesiana bisulcifrons (Erwin), B. negrei (Erwin), B. hilaris (Bates), B. belti (Bates), B. ampliata (Bates), B. strigosa (Bates), B. gruti (Bates), B. nigripalpis (Erwin), B. villiersi (Perrault), B. apicisulcata (Erwin), B. iris (Erwin), B. sculpticollis (Bates), B. sulcicostis (Bates), B. anterocostis (Erwin), B. ovatula (Bates), B. grossipunctata (Erwin), B. batesi (Erwin), B. seriata (Erwin), B. sublaevis (Bates), B. aetholia (Erwin), B. parainsularis (Erwin), NEW COMBINATIONS.Results of the Xystosomi character analysis provided impetus for a reanalysis of the classification of the major lineages of the more inclusive group, Bembidiini, to discover where the Xystosomi might belong and, in turn, if our understanding of the Bembidiini itself needed adjustment. These results are implied in Part I, but presented in detail in a separate paper, Part II. Phylogeny and Zoogeography, along with supplemental taxonomic information.

Rangeland grasshopper species richness was monitored at 10 sites in Montana, U.S.A., during 1986 through 1992, which included an extreme drought year (1988). We observed significant post-1988 drought reductions in rangeland grasshopper species richness in the eastern and south-central region of Montana where drought intensity has been increasing during the past 20 years. In the north-central region, which also experienced the 1988 drought but showed no long-term drought trend, we did not observe a post-drought reduction in overall rangeland grasshopper species richness. Thus, in terms of rangeland grasshopper species richness, the potential impact of a severe drought in a given year may depend on the timing of such an event within longer-term climatic cycles. Our findings suggest that as regional drought intensity increases temporally, there may be an increased likelihood that a single extreme drought year will not only have a profound impact on abundance but may also result in significant long-term reduction of grasshopper species richness. Our results support the hypothesis that resource limitation is a very important factor in structuring rangeland grasshopper communities in space and time.

The leaf galler Diplolepis polita (Ashmead), known only from Rosa acicularis Lindl. west of the Rocky Mountains, is recorded for the first time on the introduced, urban shrub rose Rosa rugosa Thunb. Inquilines and parasitoids commonly kill over 90% of the inducers in populations of galls found in natural habitats, whereas 55% of the galls from the urban roses contained an inducer. Differences in component communities associated with galls on domestic and wild roses are likely indicative of a recently established population in an atypical habitat. Occurrence of D. polita on this new host also provides insight into the host specificity and vagility of cynipid wasps.